TP3 - Implement eBGP for IPv4

Lab Overview

  • Objective: Implement eBGP for IPv4 topology addressing using routers via EVE-NG.

Topology Addressing Table

  • Devices & Interfaces:

    • R1:

      • G0/0/0: 10.1.2.1/24

      • S0/1/0: 10.1.3.1/25

      • S0/1/1: 10.1.3.129/25

      • Loopback0: 192.168.1.1/27

      • Loopback1: 192.168.1.65/26

    • R2:

      • G0/0/0: 10.1.2.2/24

      • G0/0/1: 10.2.3.2/24

      • Loopback0: 192.168.2.1/27

      • Loopback1: 192.168.2.65/26

    • R3:

      • G0/0/0: 10.2.3.3/24

      • S0/1/0: 10.1.3.3/25

      • S0/1/1: 10.1.3.130/25

      • Loopback0: 192.168.3.1/27

      • Loopback1: 192.168.3.65/26

Lab Scenario and Setup

  • Environment: EVE-NG utilized for simulation.

  • Hardware Requirements:

    • 3 Routers (Cisco 4221, IOS XE Release 16.9.4)

    • 1 PC for terminal emulation (e.g., Tera Term)

    • Console and Ethernet cables.

Part 1: Build the Network and Basic Configuration

  • Task: Set up topology and basic device settings.

  • Steps:

    1. Cable network as per the topology.

    2. Configure each router's settings:

    • R1 Configuration:

      • hostname R1

      • no ip domain lookup

      • Interface configurations for Loopback and Gigabit Ethernet.

    • R2 Configuration:

      • hostname R2

      • Interface configurations similar to R1.

    • R3 Configuration:

      • hostname R3

      • Note: negotiation auto for G0/0/0.

Part 2: Configure and Verify eBGP for IPv4

  • Step 1: R1 BGP Configuration

    • router bgp 1000

    • Set router-id: bgp router-id 1.1.1.1

    • Configure neighbors based on topology.

    • Advertise local IPv4 prefixes.

  • Step 2: R2 BGP Configuration

    • router bgp 500

    • Set router-id: bgp router-id 2.2.2.2

    • Configure neighbors based on topology and prefixes.

  • Step 3: R3 BGP Configuration

    • router bgp 300

    • Disable default IPv4 unicast: no bgp default ipv4-unicast

    • Configure neighbors.

  • Verifying Neighbor Relationships:

    • Use show ip route bgp to confirm prefix reception between routers. Identify lack of reception from R3 due to configuration.

Part 3: Route Summarization and Atomic Aggregate

  • Configure Route Summarization: Using aggregate-address command on routers R1 and R3.

  • Verify Route Summarization: Ensure routes summarized correctly and verified via route tables.

Part 4: Route Summarization with AS-Set

  • Shut down Serial Interfaces: Create a single path from R1 to R2 to R3.

  • Remove Previous Aggregation: Ensuring the updated summarization is reflected in routing tables.

Part 5: Advertising a Default Route

  • R2 Configuration: neighbor 10.1.2.1 default-originate

  • Verify on R1: Check routing tables for default route reception.

Questions and Explanations

  • Discuss and record differences between BGP route symbols (* and >).

  • Examine criteria for BGP route selection based on preference and path attributes.

  • Analyze configurations to verify BGP states and connections.

Conclusions

  • Complete all verification steps.

  • Discuss the benefits and behaviors of advertising default routes, route summarization, and eBGP functionalities in IPv4.